A. Field of the Invention
This invention relates generally to means for marking points or lines on surfaces for later installation of walls or partitions and the like. More particularly, the invention comprises an apparatus or tool wherein means is provided for aligning the tool with a preexisting line or mark on the floor or ceiling surface of a building and for then disposing the tool in a vertical position for subsequent marking of another line or point on the other of the floor or ceiling surfaces in vertical alignment with the preexisting line or point. The lines or points thus marked are then used to guide the installation of tracks or channels for supporting the partition or wall structures.
As generally practiced in the prior art, such lines or points require at least two persons working in cooperation with one another with one of the persons typically being required to stand upon a ladder or the like for reaching the ceiling surface, since in most buildings with which the invention is used the distance between the floor and ceiling surfaces is typically on the order of ten feet. This practice is not only time-consuming and expensive, but is also dangerous, since the workman must occassionally mark a line or point adjacent an outer edge of a floor or ceiling surface, and in multistory buildings the workmen are required to subject themselves to the danger of falling from a considerable height. Additionally, conventional means used in marking such lines and points typically comprises a plumb-bob having a flexible line with a weight suspended at the bottom end thereof, and one of the workman supports the flexible line at the ceiling surface while the other workman observes the position of the plumb-bob at the floor surface. In the building construction industry, and particularly for multistory buildings, high winds are frequently encountered and a great deal of difficulty is experienced in obtaining an accurate reading from such prior art methods.
Therefore, in view of the above problems, efforts have been made in the prior art to produce an instrument or tool which would facilitate the marking of such points and lines.
B. Prior Art
Examples of some of the prior art efforts are exemplified in U.S. Pat. Nos. 1,952,745, 2,245,646, 2,846,770, 3,277,579, 3,328,887 and 3,492,737. However, although these patents do solve some of the problems noted above, they still have one or more disadvantages. For example, some of the devices are not very accurate in use and do not provide ease of operation. Others are relatively complex and expensive in construction, and still others are limited in the functions which they are capable of performing. Moreover, with all of the patents noted, more than one person would apparently still be required in order to mark lines between points determined with the patented instruments. In other words, while some of the patents disclose that they are intended to be used by one person for marking the lines at designated edges at the top and bottom of the instruments, none of them suggests any means for holding or supporting a chalk line or the like whereby a line may be struck between marked points. Accordingly, one or more workmen would presumably still be required to mount a ladder in order to support a chalk line at the ceiling surface for striking a line on the ceiling surface between two marked points.